Influence of seasonality and climate on captures of wood-boring Coleoptera (Bostrichidae and Curculionidae (Scolytinae and Platypodinae)) using ethanol-baited traps in a seasonal tropical forest of northern Thailand

ABSTRACT

Insects in the tropics usually have continuous generations throughout the year. We reanalyzed published data of wood-boring beetles, belonging to three taxonomic groups (Bostrichidae; Curculionidae: Scolytinae, Platypodinae), that were captured by ethanol-baited traps continuously set for three years and collected every two weeks in the lowland montane forest in northern Thailand. Because trap captures seemed to have 1-yr cycle, we hypothesized that 1-yr cycle of climate had caused 1-yr cycle in the trap captures. To test this hypothesis, cycles of both total trap captures (TTC) and of each species, synchrony in time-series trap captures, and causality of temperature and rainfall to the TTC were determined. Eighty-nine species were captured over the three years. Among 55 species (>2 individuals), 30 species showed the greatest peak of spectral density at 1-yr, but only three were significant. Some species had (a) cycle(s) shorter than one year. However, 20 species making up 69.7% of TTC and 38 species making up 91.1% of TTC showed significant synchrony with TTC diagnosed by the Phillips-Ouliaris cointegration test and Pearson’s correlation function, respectively. Temperature, rainfall, and season (solar elevation angle) showed significant causalities, the effect of season being the strongest. Both temperature and rainfall positively influenced TTC with lags. These results indicate that seasonality in temperature and rainfall caused a 1-yr cycle in flying beetles of a majority of the more abundant species, and synchrony among species, which resulted in the 1-yr cycle of TTC. The revolution and tilt of the earth was a likely driving force.

KEYWORDS:

• Bark beetle
• ambrosia beetle
• temperature
• rainfall
• 1-year cycle

Acknowledgments

We express our sincere thanks to the two anonymous reviewers and four editors for their valuable comments to the earlier versions of this manuscript. Former students at Kasetsart University helped sorting insects. Biing-Tzuang Guan provided useful information on spectral density analysis. We also thank them.

Disclosure statement

No potential conflict of interest was reported by the authors.

Correction Statement

This article has been republished with minor changes. These changes do not impact the academic content of the article.

Additional information

Funding

This work was supported by the Japan Society for the Promotion of Science [16H02760]; Japan Society for the Promotion of Science [Core-to-core Project (FY2019―FY2021)]; Japan Society for the Promotion of Science [Core-to-core Project (FY2016―FY2018)]; Japan Society for the Promotion of Science [23255011].